The present invention generally relates to vascular access ports. In particular, the present invention relates to vascular access ports having means for needle detection.
Implantable vascular access ports (VAP) are used extensively in the medical field when recurrent infusions of therapeutic agents into a patient's circulatory system are required over extended periods of time. Such VAPs generally include a housing containing a reservoir and septum, with a catheter extending from the housing. The VAP housing is implanted in a subcutaneous pocket at an accessible location such as the arm, and the catheter extends from the housing to a remote vascular location to provide convenient, repeatable access to the patient's venous or arterial system deep in the body. In the subcutaneous pocket, the septum of the VAP may be pierced by a needle that is coupled via appropriate tubing to a therapeutic agent source in an intravenous bag or infusion pump, for example, so that the therapeutic agents may be administered. Such a vascular access system may be used in the home or other outpatient settings, as well as inpatient hospital settings.
Because the VAP resides in a subcutaneous pocket, it is not visible to the naked eye, with the exception of a slight contour that may be seen and felt on the skin overlaying the VAP. However, palpitation of the skin contour does not readily discern the septum of the VAP, and it is not possible to visually confirm with certainty that a needle has been correctly inserted through the septum and into the internal reservoir of the VAP. Thus, it is not uncommon for the health care practitioner to err when inserting the needle. An improperly inserted needle may result in the infusion of a drug into the subcutaneous space around the VAP. Once in the subcutaneous space, the drug may cause the patient pain and suffering, and with some drugs, even severe tissue necrosis. Presently, careful palpitation is the standard method used by practitioners to identify a properly inserted needle, and this method is susceptible to error.
Another significant problem with conventional VAPs is inadvertent removal of the needle from the VAP during infusion. Drug infusions are typically administered over a long period of time (relative to a single injection), and are sometimes performed outside a hospital setting. The needle may be secured to the skin over the VAP by adhesive tape, for example, so that the patient or nurse doesn't need to manually hold the needle in place. Once the needle is secured, the patient often moves around, whether it be slight movements in a recliner or bed, or more significant movements in attending to daily activities. Such movements may cause the infusion tubing to pull on the needle, potentially causing the needle to be inadvertently removed from the VAP. When this occurs, the patient and/or the nurse may be unaware of the accidental removal, and the infusion pump may continue to administer the drug. Thus, the patient may not receive the prescribed dosage and it may be difficult to determine exactly how much of the dosage was delivered to the patient before the needle was accidentally removed from the VAP.
Thus, there is a need for a VAP system that permits the practitioner to confirm that the needle has been correctly inserted through the septum and into the internal reservoir of the VAP, and a VAP system that notifies the patient and/or practitioner if the needle has been accidentally withdrawn.